Cable Slack
 

Hey guys,

had a clipless moment last night. Saw a green traffic light and assumed that the traffic would start moving by the time I got to it. It didn't and I didn't leave enough time to clip out.
This caused a lovely slow fall to me left hand side in which the bike (Spesh Secteur) got bashed against the kerb.

Everything seemed *mostly* fine - I had to re-centre my rear brake caliper but that was it.
Since the moment though, I'm having trouble with my rear brake cable. Basically, the cable running under the top tube seems particularly slack, even though the brake pads are almost touching the rims (so, if I try to adjust the cable tension via the barrels they start rubbing the rims). When I pull on my left brake (Shimano 105), the brake engages and cable becomes tight. As I let the shifter go, it seems to put even more slack in the cable for about 10 secs or so, during which time the shifter moves 'freely', i.e. if you immediately pull the lever, it will move around 45 degrees instantly before starting to tighten the cable and engage the brakes.

Could this be something do with the cable getting a jolt at the shifter end during the fall? It always seems to be my damn shifters that get knocked when I have these moments....

Thanks

Could be a number of different things, but most likely something happened with the cable housing. Check to see if there are any kinks or bends in the housing, instead of a rounded arc. This causes the cable to not move freely within the housing, resulting in what you described above. Simlarly, see if the housing got twisted or routed in some funky way, this can happen near the front end of the bike.

If its not either of these, it could be that the inside of the housing is dirty or corroded, causing the cable to not move freely, and it could be that you just didn't notice it until after the "crash" :). If there is corrosion, replace both the cable and the housing.

+1 for bent cable housing.

Another possibility is that the brake caliper itself was damaged and either one of the arms or a pivot bolt was bent. Disconnect the cable at the caliper and see if the brake arms move freely with hand pressure. If the caliper itself is damaged you may be able to readjust the pivot bolts or may have to replace it entirely.

badhorsy, As you fell to the left, the side most rear brakes attach to the cable housing, I think the caliper's arm may've been bent upwards/inwards causing the cable slack. Compare with your front caliper. It's another debate if it's bent as to whether it'll be fine as is or should be replaced.

Brad

Check the housing ferrules, too, especially the one at the caliper. I've found these easily come out of their seated position in the housing stops when doing certain maintenance. When your caliper struck the curb, the cable lost tension. Combined with the jostling of the impact, this may have allowed the housing ferrule to lose its fully seated position.